Image source: Valencell

Sensors under pressure, interview with Valencell President & Co-Founder Dr. Steven LeBoeuf

Which technologies will win the race to measure blood pressure from the wrist? There are a few different approaches to tackling what seems to be the next big frontier in health tracking. I spoke to Valencell President and Co-Founder Dr. Steven LeBoeuf to get his take on the matter.

We reported back in January on a new sensor that is being developed by Valencell. Announced at CES 2021, it will allow smartwatches and fitness trackers to take blood pressure readings with the same accuracy as traditional cuffs – no calibration needed.

That is a major difference compared to some of the current approaches. For example, Samsung has blood pressure tracking functionality on its most recent crop of Galaxy watches. However, it is far from ideal or easy to use. In order for it to work properly, you must install a separate smartphone app and perform a calibration with a traditional cuff each month.


Hypertension – an important public health concern

Hypertension is a global health issue. It increases the risks of heart, brain, kidney and other diseases.

The World Health Organization estimates there are some 1.13 billion individuals worldwide with the condition. And only about one out of five of them have this under control.

Part of the issue is that many people do not know they suffer from high blood pressure until it is too late. That is why hypertension is sometimes called a silent killer. Early indication is important in preventive care but often there are no obvious warning signs or symptoms.

Essential reading: Best fitness trackers and health gadgets

The best way to mitigate these risks is to measure your blood pressure on a regular basis. But let’s be honest? How many of us really take the time to strap on a traditional blood pressure cuff every few weeks or months?

Taking readings is an unwieldy process. Unfortunately, there has been no meaningful innovation in blood pressure technology for decades. That’s the bad news. The good news is that thanks to Valencell and a number of other health tech pioneers, this is about to change.


Valencell’s blood pressure measurement solution

In a press release at the start of this year, Valencell went into more detail about its upcoming blood pressure management solution. This is technology that works with “traditional” PPG (photoplethysmography) sensors at the ear, wrist or even finger tips. These are the same sensors that are currently used to capture data on heart rate, heart rate variability, blood oxygenation and respiration rate.

Sensors under pressure, interview with Valencell President Dr. Steven LeBoeuf
Image source: Valencell

The company says it has upgraded PPG sensors to enable them to capture blood pressure readings alongside these other metrics. Info captured from the sensor is combined with a person’s vitals stats and inertial sensor information to arrive at the estimates. Which, Valencell says, are as accurate as those taken with traditional cuffs.

This is great news. Unless, of course, you make a living from selling traditional blood pressure cuffs.

When will we see this new sensor technology in our smartwatches, fitness trackers and other wearables? I spoke to Dr. Steven LeBoeuf to find out. What follows is my Q&A.

It has been a while since we’ve seen something truly new on the health sensor front. Most wearables these days track pretty much the same data. This includes steps, activity, sleep, heart rate, blood oxygen and in some cases ECG.

Little else has been added to this list over the past couple of years. Is this about to change?

We’re often asked what’s the next health sensor technology that will make an impact on patient care. Our belief is that the current sensor modalities, particularly motion-tolerant photoplethysmography (PPG), are vastly underutilized. Nearly a decade ago, wearable PPG  sensors first demonstrated the ability to accurately estimate RR-intervals for heart rate variability (HRV) and atrial fibrillation assessments, but products leveraging this development are just now entering the marketplace.

While it is true that Valencell has developed a powerful new PPG-metric with it’s cuffless, calibration-free, PPG-based blood pressure monitoring solution, the future impact of wearable sensor technology will be shaped less by brand-new biometrics and more by the application of a few key biometrics towards public health use cases. As just one example, researchers have already shown that screening for various health conditions can be achieved with reasonable accuracy utilizing accurate heart rate, meta data, and activity context alone.

We see blood pressure as the next frontier in wrist sensor technology. Most often two approaches are mentioned. The use of ECG – Pulse Transit/Arrival Time (presently being studied by Fitbit) and photoplethysmography (PPG) sensors that analyze blood volume flows. Your solution falls into the latter camp?

That’s correct. Valencell’s cuffless, calibration-free blood pressure technology does not rely on ECG signals or ECG sensors. In contrast, our solution requires 3 inputs: PPG data, subject meta data (such as age, weight, and height), and accelerometry data. Our technology was designed such that a particular version of Valencell’s Benchmark® PPG sensor module will be sufficient (as a standalone sensor) for accurately monitoring BP.

Valencell’s new sensor allows smartwatches to take blood pressure


No calibration needed

What is the difference between the two approaches in terms of accuracy of blood pressure readings and the potential to track other health metrics?

Frankly, there is insufficient data in published literature to objectively compare the accuracy statistics of the two methods. By leaps and bounds, the biggest difference between the two approaches is that Valencell’s all-PPG approach does not require any calibration in order to provide cufflike accuracy.

Valencell believes a calibration-free approach is critical for consumer-level and remote patient monitoring applications, where it is simply impractical to rely on end user calibration for accurate blood pressure monitoring. However, calibrated solutions have their place in the market, as they potentially offer greater precision for use cases where high-resolution may be critical, common to hospitals and clinics.

It is also worth noting that a late-breaking innovation (co-developed by Valencell and SunTech Medical) has recently blazed new trails in high-precision ambulatory monitoring. This approach combines the best of BP cuffs and PPG sensors in an “augmented BP monitoring” solution, where the PPG sensor continuously adapts to ongoing cuff measurements. We’ve been demoing this technology together across the world.

So you see the lack of the need to calibrate Valencell sensors as a critical factor as compared to current market solutions?

We view calibration requirements as a showstopper for mass consumer adoption of BP monitoring in wearables. Not only does a calibrated solution require the end user to own two BP monitors (one to wear and the other as a standard BP cuff for calibration), but the calibration process is irksome and nontrivial, often requiring professional assistance to get it right. And if you calibrate incorrectly, all of your resulting data is digitized rubbish. Moreover, there’s simply not enough population data available in the literature to predict how frequently a calibration reading must be taken.

Have you developed new sensors or is the update software based? If it is the latter – does this mean existing devices that pack Valencell heart rate sensors will gain the ability to measure blood pressure?

Valencell’s BP technology is based on a specific Valencell sensor and BP-related software advancements. Devices that have the right Valencell sensor embedded may be able to be upgraded to monitor blood pressure, but it will be up to the device makers to make those decisions.

Are these measurements on-demand? Or is it automatic blood pressure tracking, for example while a person sleeps?

The BP readings can be either on-demand or automatic, depending on the patient experience enabled by the device/solution that has the Valencell technology embedded. The technology does require the individual to be still and have the sensor close to heart level, but when that is detected, the Valencell sensor can take an automatic reading.


Hypertension management will change more in the next 5 years than in the last 100 years!

How close are we to seeing this in a commercial product? When do you expect first fitness trackers and smartwatches with Valencell blood pressure measurements to become available?

We expect this technology in the market in 2022.

The FDA in the US can be a tough nut to crack – some companies have faced waiting times of over a year to get their sensor tech approved. Do you anticipate such problems?

We have opened discussions with the FDA in advance of our regulatory submission in an effort to ensure the FDA is comfortable with Valencell’s approach, data, and potential public health benefits of the technology.

Who do you see as your main competition? We’ve heard a lot about Rockley Photonics in recent months.

They are also planning to release technology that can track blood pressure and more. But it seems to be yet another approach. Rockley Photonics have developed a spectrometer-on-a-chip platform they hope will be built into commercial wearables in the first half of next year.

When it comes to PPG-based BP monitoring, Valencell has a significant head-start, as we’ve been investigating the approach since 2009 and have collected more than 20,000 professional BP + PPG datasets to build our models.

We see the competitive landscape in 3 basic “buckets”: 1) Sensor companies like Rockley, Maxim, AMS and others. 2) Medical device makers, including BP cuff companies, traditional med device companies, and startups. 3) Consumer device makers who are working on adding BP monitoring to existing devices, like the Apple Watch or Google/Fitbit devices.

Our barriers to entry include our vast patent portfolio, trade secrets, and the overwhelming hurdles required (especially in terms of data collection) to get the machine models to actually work.

Where do you see sensor tech heading in the coming years? What other health stats and biomarkers are we likely to keep tabs on in the near future?

As mentioned above, there seems to be ample opportunity to leverage additional capabilities of existing sensor technologies for more advanced insights and you’ll see more “sensor fusion”, using multiple sensor modalities together to generate a more comprehensive physiological picture. In addition, the combination of advanced biometric sensor technologies and AI/machine learning applied to wearable sensor data is beginning to yield impressive results. You’ll see these technologies applied primarily toward metabolic conditions, cardiovascular disease, and vascular disease/stroke.

Even though the future of wearable R&D will rely heavily on HW and SW advancements, we see consumer demand centering more around personalized health management use cases, such as personalized digital therapeutics, and less around the wearable solutions themselves. A good example is hypertension management, which we see changing more in the next 5 years than in the last 100 years.

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